Source : Webster's Revised Unabridged Dictionary (1913)

Sphericity \Sphe*ric"i*ty\, n. [Cf. F. sph['e]ricit['e].]
   The quality or state of being spherial; roundness; as, the
   sphericity of the planets, or of a drop of water.

Source : WordNet®

sphericity
     n : the roundness of a 3-dimensional object [syn: {sphericalness},
          {globosity}, {globularness}, {rotundity}]